1. Field of the Invention
The present invention relates to an image forming apparatus comprising an intermediate transferring member to which an image is transferred by contacting it to a photosensitive member.
2. Description of Related Art
A copy machine, a printer or the like, which uses an electrophotographic system has been known. That is, after a latent image is formed on a uniformly charged photosensitive drum (photosensitive member) by a laser, an LED or the like, the image is developed by attracting a toner to the photosensitive drum. A document data is printed by transferring the image to a transfer medium, such as a paper and by fixing the toner.
In the above-described image forming apparatus, the image forming apparatus for forming an image by transferring the image to a transfer medium, such as a paper, after the toner for developing the image is intermediately transferred to the intermediate transferring member, such as an intermediate transferring belt or the like, controls the rotational actuation of the photosensitive drum in consideration of the vibration of the photosensitive drum, which is caused by the disturbance of a mechanical motion.
When the toner for developing the image on the photosensitive drum is intermediately transferred to the intermediate transferring belt, the intermediate transferring belt is pressed to the photosensitive drum. However, when the disturbance is caused by pressing the intermediate transferring belt, the photosensitive drum is more vibrated as compared with the other disturbances. Therefore, it was required to widely design the control system for the rotational actuation of the photosensitive drum by assuming the disturbance during the pressing of the intermediate transferring belt. In order to solve the problem, the rotational actuation is controlled by using a high speed operation unit, such as a DSP (Digital Signal Processor). In general, such a high speed operation unit is expensive.
If there is no disturbance caused during the pressing of the intermediate transferring belt, the range of the whole disturbance can be limited. Further, it is possible to carry out the rotational actuating control for the photosensitive drum in detail.
In order to solve the above-described problems, an object of the present invention is to realize the stability of the rotational actuating control for the photosensitive drum at a low cost.
That is, in accordance with the first aspect of the present invention, an image forming apparatus comprises:
a photosensitive member;
an intermediate transferring member to which an image formed on the photosensitive member is transferred;
a press/release operation controlling section for controlling a pressing of the intermediate transferring member to the photosensitive member and for controlling a release of the pressing;
a rotational actuation controlling section for controlling a rotational actuation of the photosensitive member;
a judging section for judging a finish of a pressing operation carried out by the press/release operation controlling section; and
a start timing controlling section for starting a control for the rotational actuation of the photosensitive member by the rotational actuation controlling section when the judging section judges the finish of the pressing operation.
According to the present invention, because the rotational actuation control for the photosensitive member is started after the pressing operation of the intermediate transferring member to the photosensitive member is finished, it is not required that the vibration caused by pressing the intermediate transferring member to the photosensitive member should be considered when the rotational actuation control is carried out for the photosensitive member. Thereby, it is possible to improve the stability of the rotational actuation control for the photosensitive member.
The image forming apparatus may further comprise: a time measuring section for measuring an elapsed time from a start of an image forming process;
wherein the judging section judges whether the pressing operation of the intermediate transferring member is finished in accordance with the elapsed time measured by the time measuring section.
According to the present invention, the required time for finishing the pressing operation of the intermediate transferring member from the start of the image forming process is previously set to judge whether the required time elapses from the input of the start command for the image forming process. Therefore, it is possible to judge whether the pressing operation of the intermediate transferring member is finished and to determine the start timing of the rotational actuation control for the photosensitive member.
The image forming apparatus may comprise: a stop timing controlling section for stopping the control carried out by the rotational actuation controlling section, when a releasing operation of the intermediate transferring member is started by the press/release operation controlling section.
According to the present invention, it is possible to stop the rotational actuation control for the photosensitive member when the releasing operation of the intermediate transferring member is started. Therefore, when the rotational actuation control for the photosensitive member is carried out, it is not required that the vibration of the photosensitive member, which is caused by releasing the intermediate transferring member from the photosensitive member, should be considered when the rotational actuation control is carried out for the photosensitive member. It is possible to improve the stability of the control.
The rotational actuation controlling section may control the rotational actuation of the photosensitive member by using a feed back control and a feed forward control.
The feed back control and the feed forward control may be designed in accordance with a transmitting property of a vibration of the intermediate transferring member, the vibration being caused during the pressing.
In accordance with the second aspect of the present invention, an image forming apparatus comprises:
a photosensitive member;
an intermediate transferring member to which an image formed on the photosensitive member is transferred;
a press/release operation controlling section for controlling a pressing of the intermediate transferring member to the photosensitive member and for controlling a release of the pressing;
a rotational actuation controlling section for controlling a rotational actuation of the photosensitive member;
a judging section for judging a finish of a pressing operation carried out by the press/release operation controlling section; and
a start timing controlling section for starting a control for the rotational actuation of the photosensitive member by the rotational actuation controlling section;
wherein the rotational actuation controlling section controls the rotational actuation of the photosensitive member by using the feed back control and the feed forward control; and
wherein the start timing controlling section starts the feed forward control when the judging section judges that the pressing operation is finished.
According to the present invention, for example, when the image forming process is started, the control for the rotational actuation is started in accordance with the feed back control. Further, when the pressing operation is finished, the feed forward control is started. Therefore, it is possible to carry out the feed back control for the rotational actuation of the photosensitive member in consideration of the vibration caused by pressing the intermediate transferring member to the photosensitive member. Therefore, for example, it is possible to apply the image forming apparatus to the case that the required time for judging the finish of the pressing operation from the pressing of the intermediate transferring belt to the photosensitive member is limited.
The image forming apparatus may further comprise: a time measuring section for measuring an elapsed time from a start of an image forming process;
wherein the judging section judges whether the pressing operation of the intermediate transferring member is finished in accordance with the elapsed time measured by the time measuring section.
The image forming apparatus may further comprise: a stop timing controlling section for stopping the control carried out by the rotational actuation controlling section, when a releasing operation of the intermediate transferring member is started by the press/release operation controlling section.
The feed back control may be designed in accordance with a first transmitting property of a first vibration of the intermediate transferring member and a second transmitting property of a second vibration of the intermediate transferring member, the first vibration being caused during the pressing and the second vibration being caused during the release; and
the feed forward control may be designed in accordance with the first transmitting property.